A Facile Synthetic Approach for Zn2TiO4@NiCo2O4 Core‐Shell Nanoparticles Using Layered Double Hydroxide Precursors and Studies on Their Peroxidase‐Like Activity

Zn₂TiO₄@NiCo₂O₄ core-shell nanoparticles, synthesized using Zn₂TiO₄@Ni−Co-LDH as precursors show better peroxidase-like activity compared to pure NiCo₂O₄ nanoparticles and natural horse radish peroxidase enzyme.

Abstract

In the present work, a facile synthetic approach has been developed for Zn₂TiO₄@NiCo₂O₄ core-shell nanoparticles (NPs) using layered double hydroxide (LDH) as precursors. The Zn₂TiO₄ microspheres (ZTS) constitute the core and the shell consists of NiCo₂O₄ nanoparticles. X-ray diffraction (XRD) results confirm presence of both Zn₂TiO₄ and NiCo₂O₄ phases in Zn₂TiO₄@NiCo₂O₄ core-shell nanoparticles. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analyses indicate formation of hierarchical porous shell structure of NiCo₂O₄ with varying thickness (132±20 nm to 171±35 nm) on the Zn₂TiO₄ spheres. Optical studies indicate bandgap of ~2.2 eV corresponding to NiCo₂O₄ nanoparticles in the Zn₂TiO₄@NiCo₂O₄ core-shell nanoparticles. The Zn₂TiO₄@NiCo₂O₄ core-shell nanoparticles possess high surface area (124 m²/g to 160 m²/g) as measured from Brunauer-Emmett-Teller (BET) analysis. Magnetic studies of Zn₂TiO₄@NiCo₂O₄ core-shell nanoparticles indicate soft ferromagnetic and hard ferromagnetic behavior at 300 K and 5 K, respectively. The Zn₂TiO₄@NiCo₂O₄ core-shell nanoparticles act as nanozyme and they exhibit better peroxidase-like activity as compared to pure NiCo₂O₄ NPs and natural horseradish peroxidase (HRP).

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